Linq update query - Is there no pretty way?

Question

Hello

I want to update my database using a LINQ2SQL query.

However this seems for some reason to be a very ugly task compared to the otherwise lovely LINQ code.

The query needs to update two tables.

tbl_subscription
(
   id int,
   sub_name nvarchar(100),
   sub_desc nvarchar(500),
   and so on.
)

tbl_subscription2tags
(
   sub_id (FK to tbl_subscription)
   tag_id (FK to a table called tbl_subscription_tags)
)

Now down to my update function a send a tbl_subscription entity with the tags and everything.

I can't find a pretty way to update my database..

I can only find ugly examples where I suddenly have to map all attributes..

There most be a smart way to perform this. Please help.

C# Example if possible.

I have tried this with no effect:

public void UpdateSubscription(tbl_subscription subscription)
    {
        db.tbl_subscriptions.Attach(subscription);
        db.Refresh(System.Data.Linq.RefreshMode.OverwriteCurrentValues, subscription);
        db.SubmitChanges(System.Data.Linq.ConflictMode.FailOnFirstConflict);
    }

Source for this code is here: http://skyeyefive.spaces.live.com/blog/cns!6B6EB6E6694659F2!516.entry

Answer 1

Why don't just make the changes to the objects and perform a SubmitChanges to the DataContext?

using(MyDataContext dc = new MyDataContext("ConnectionString"))
{
  foreach(var foo in dc.foo2)
  {
   foo.prop1 = 1;
  }
  dc.SubmitChanges();
}

Otherwise you need to tell us more about the lifecycle of the object you want to manipulate

edit: forgot to wrap in brackets for using

Answer 2

Unless I'm misunderstanding your situation, I think that citronas is right.

The best and easiest way that I've found to update database items through LINQ to SQL is the following:

1. Obtain the item you want to change from the data context
2. Change whatever values you want to update
3. Call the SubmitChanges() method of the data context.

---

Sample Code

The sample code below assumes that I have a data context named DBDataContext that connects to a database that has a Products table with ID and Price parameters. Also, a productID variable contains the ID of the record you want to update.

using (var db = new DBDataContext())
{
    // Step 1 - get the item from the data context
    var product = db.Products.Where(p => p.ID == productID).SingleOrDefault();
    if (product == null) //Error checking
    {
        throw new ArgumentException();
    }

    // Step 2 - change whatever values you want to update
    product.Price = 100;

    // Step 3 - submit the changes
    db.SubmitChanges();
}

Answer 3

I found out that you can use "Attach" as seen in my question to update a table, but apparently not the sub tables. So I just used a few Attach and it worked without having to run through parameters!